A composition can mean an essay written in school. To describe a piece of writing say in a book or magazine as a composition would probably insult the writer.
First of all, suffuse is a $5 word to me. That is, very few people know the actual meaning of this word. So it is too complicated for normal writing. I had to look up its meaning myself and it means a spreading of color or moisture not spreading of plants. So unless you are being poetic when using this sentence, it is not the correct usage of the word.
A better sentence would be
Swampy areas are filled with flora.
I am not certain you wanted the last sentence evaluated (seems like a mission statement for your school) but it is a very good sentence.
Student or Learner